2015 Toyota Sienna Engine Oil Cooler Line Replacement Cost

Engine oil lubricates the moving parts inside the engine of a car, truck, or SUV. The oil also helps to keep the engine cool. On some vehicles, an engine oil cooler helps to prolong the life of the oil and preserve its ability to lubricate. An engine oil cooler line connects the engine and the oil cooler.

Engine oil breaks down over time. Heat produced in the engine speeds up this breakdown of the oil and decreases its ability to effectively lubricate the moving parts of the engine. This is especially true with a high performance car or hard-working truck. So, oil is circulated out of the engine by way of one oil cooler line, through the oil cooler, and back to the engine through another line. The oil cooler can be a stand-alone unit, or it can be built into the vehicle's radiator. The oil cooler is made up of a passageway of tubes laced back and forth across a matrix of thin aluminum plates, or "fins", with spaces between them. The hot oil passes through the tubes and the heat is transferred from the oil, through the tubes, and to the fins. Air passing through the cooler removes the heat from the cooling fins. The cooled oil returns to the engine. This system is the same concept as that of an automatic transmission cooler found in most vehicles.

Most of the time, a bad oil cooler line will leak oil from one of its connections. The seals can deteriorate and cause a leak. The cooler lines can become corroded over time, or they can crack. A low oil condition can result from a leak and trigger a warning light on the dash. The oil cooler on some vehicles shares engine coolant with the radiator. Leaking engine coolant or antifreeze might be a symptom of a bad line. in that case, a low coolant warning light might come on. And, in extreme cases, engine overheating can be a sign that a cooling line is damaged.